V4L/DVB (9878): gspca - vc032x: Fix frame overflow errors with vc0321.

The vc0321 sends some additional data after sending the complete
frame, we ignore this.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Jean-Francois Moine <moinejf@free.fr>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>